The Diaspora: Shattered Armistice Website offers the release of this community-created Windows, OS X, and Linux game (though the Linux version is not compiled) set in the Battlestar Galactica universe. The site is working as of this writing, but it has been up and down all day, so some patience may be required to contend with the demand for this. Here's word on what this features:

Fly the MK VII Viper, the Raptor or the new MK VIIe strike variant.

Take part in furious battles against Cylon forces.

Play multiplayer missions against your friends as Colonial or Cylon forces.

Completely voice acted throughout.

Original soundtrack inspired by the show

Create your own missions and share them with the included mission editor.